flatland.envs.graph.graph_simplification module

class flatland.envs.graph.graph_simplification.DecisionPointGraph(g: MultiDiGraph)

Bases: object

Overlay on top of Flatland 3 grid where consecutive cells where agents cannot choose between alternative paths are collapsed into a single edge. A reference to the underlying grid nodes is maintained. The edge length is the number of cells “collapsed” into this edge. See DecisionPointGraphEdgeData.

Attributes

g: nx.MultiDiGraph

The decision point graph. Nodes have type GridNode and edge data has an attributed d of type DecisionPointGraphEdgeData.

static fromGraphTransitionMap(gtm: GraphTransitionMap) → DecisionPointGraph

Factory method to derive DecisionPointGraph from GraphTransitionMap.

Parameters

gtm: GraphTransitionMap

The Flatland 3 graph transition map.

Returns

The overlaid decision point graph.

class flatland.envs.graph.graph_simplification.DecisionPointGraphEdgeData(path: List[Tuple[int, int, int]], len: int)

Bases: object

The edge data of a decision point overlay graph.

Attributes

path: List[GridNode]

The list of collapsed cells, starting on a facing switch (e.g. where a decision has been taken upon entering).

len: int

Number of collapsed cells.